1. Field
Apparatuses and methods consistent with exemplary embodiments relate to 3-dimensional (3D) image acquisition apparatuses and 3D image acquisition methods for simultaneously obtaining a color image and a depth image, and more particularly, to compact 3D image acquisition apparatuses capable of simultaneously obtaining a color image and a depth image in a single shooting operation so as to have a compact configuration and to increase the speed of obtaining a 3D image, and 3D image acquisition methods using the same.
2. Description of the Related Art
Currently, since 3D display apparatuses capable of displaying stereoscopic images are increasingly being developed and are in more demand, people are interested in 3D content. As such, research is being conducted on 3D image acquisition apparatuses, e.g., 3D cameras, for allowing general users to directly generate 3D content. When an object is photographed, a 3D camera may obtain an image including typical 2-dimensional (2D) color information (hereinafter referred to as a color image) and an image including depth information (hereinafter referred to as a depth image) together.
Depth information regarding distances from surfaces of an object and a 3D camera may be obtained by using a stereo vision method using two cameras or an optical triangulation method using patterned light and a camera. In the optical triangulation method, although a color image and a depth image is simultaneously obtained in a single shooting operation and thus the speed of obtaining a 3D image is high, the accuracy of depth information may be greatly reduced if a distance to an object is large, and precise depth information may not be easily obtained due to high dependency on a surface state of the object. Also, since a sufficient distance has to be ensured between a light source and a light detector, a compact configuration may not be easily achieved.
In order to solve the above problems, a time-of-flight (TOF) technology has been introduced. According to TOF technology, a TOF until light illuminates an object and light reflected from the object reaches a light receiving part and is measured. In order to extract depth information, the TOF technology includes a series of operations such as projecting light having a certain wavelength (e.g., near infrared (NIR) light having a wavelength of 850 nm) onto an object by using an illumination optical system including a light emitting diode (LED) or a laser diode (LD), receiving the light by a light receiving part light having the same wavelength as that of the projected light, and then modulating the received light by using a modulator. Various TOF technologies have been suggested according to this series of light processing operations.
However, a TOF technology requires at least three infrared (IR) images to obtain one depth image. For example, one depth image may be obtained by photographing an object by using at least three beams of IR light having the same wavelength and different phases. Accordingly, since at least three shooting operations are required to obtain one depth image, a total exposure time is increased. As such, the TOF technology is not useful to photograph a moving object.